Rebels from the Ugandan Lord's Resistance Army (LRA) have killed 189 people during three separate raids in a remote part of Democratic Republic of Congo, the UN and aid agencies said today.

Attacks on the villages of Faradje, Doruma and Gurba, in north-eastern Congo, between December 25 and 27 came as LRA rebels fled a regional military offensive by neighbouring states.

Numerous adults and at least 20 children were kidnapped during the raids - a signature of the militia, which is led by Joseph Kony, a self-proclaimed mystic who is wanted for war crimes by the international criminal court.

According to the UN humanitarian agency OCHA, the worst attack took place at Doruma, 25 miles from the Sudanese border, on Boxing Day, killing 89 people. Ugandan army officials and aid workers said dozens of the victims had been sheltering inside a Catholic church and were hacked to death with machetes.

The LRA terrorised northern Uganda for almost 20 years from the late eighties, killing and maiming more than 10,000 people, abducting 20,000 children to use as soldiers and sex slaves, and forcing at least 2 million civilians to live in camps.

Most of the victims were Acholis – the very people the rebels claimed to be acting for against the government of President Yoweri Museveni.

In 2006 the reclusive Kony emerged in South Sudan, calling himself "a man of peace" and agreeing to a truce with the Ugandan army. But during more than two years of tortuous negotiations on disarmament and justice he failed to attend several planned signing ceremonies intended to formally end the rebellion.

Each time his negotiating team would insist that ICC warrants against Kony and two senior commanders remained the sticking point. Meanwhile, Kony's ragtag army, small yet extremely skilled in bush warfare, continued to launch raids in Sudan, Congo and Central African Republic.

On December 14 regional patience finally ran out. Uganda, South Sudan and Congo announced a joint offensive to flush the rebels out of their bases in the Garamba national park, in north-eastern Congo.

Operation Lightning Thunder, which was led by Uganda, saw airstrikes by MiG fighters and attack helicopters against several LRA hideouts, including Camp Swahili, Kony's reported base.

While the rebels were forced onto the run, no LRA senior figures were reported to have been killed or captured.

Before the operation human rights experts and analysts applauded the regional cooperation, but warned that the attacks could result in significant civilian casualties and retaliatory raids.